Improvement in key-hole guards



M. scnou & T. WEST.

KEY-HOLE GUARDS. v I No.181, 728. Patenteci Aug.29,1876.

UNITED STATES PATENT MATHIAS soHoU AND THOMAS wnsr, or EueLIsnTowunEw JERSEY.

meovmzm IN leer-HOLE GUARDS.

Specification forming part of Letters Patent No. 181,728, dated August 29, 1876 application filed August 2, 1876.

To all whom it may concern:

Be it known that we, MATHIAS SGHOU and THOMAS WEST, of Englishtown, in the county of Monmouth and State of New Jersey, have invented certain new and useful Improvements in Key-Hole Guards, of which the following is a full, clear, and exact description:

This inventionis in the nature ofan improvement on the device shown in Patent No. 178,334, of June 6, 1876, granted to Mathias Schou, assignor of onehalf of his right to Thomas West.

The invention consists in a key-hole guard composed of a sliding, removable, and adjustable slotted guard-plate having a tapering hub, a guard-plate carrying-stem having a retaining-lug, and a bit and hub, the three several parts being connected tog'ether so as to be readily separable, substantially as and for the purposes hereinafter specified.

In the drawings illustrating our invention,

Figure 1 is a perspective view; Fig. 2, an enlarged side view, partly sectional Fig. 3, a rear-end View, showing the parts in position for insertion in the lock; and Fig. 4, a front view of the guard-plate.

The letter a designates the hub carrying the bit 12, which latter is made with a tongue, 0, extending forward of the hub. 01 is a threaded socket in hub a, adapted to receive a screw, g, formed on the stem f. The stem f has the retaining-lug h, and a groove, 0, said groove extending longitudinally of the stem from its outer end to the lug; and said lug .projectsfrom the stem at right angles to the groove. '5 is the guard-plate, having a smoothly-bored taperinghub, la, and sliding easily on the stem f. Said guard-plate has a slot, m, formed in its face, through which the bit-tongue 0 projects when the guard is applied, so as to lock the two. A feather, n, is made in the bore of the hub k, of a size and shape to fit in the groove 0, whereby the stem f and guard-plate are made to turn together. lis a nut, adjustable against the hub k, and on the stem j, which is screw-threaded for the purpose. 7 v

To apply this guard to a key-hole the guardplate is turned at right angles to the bit, so

as to cause the lug h of stem f to register or come in line with the bit, as shown in Fig. 3, when the bit, 850., may be inserted in the keyhole. The guard-plate is then turned back,

and the nut Zscrewed up until the guard-plate is brought tightly against the lock-case.

It will be understood that the guard-plate shall be turned sufficiently far to bring its slot in line with the tongue, so that the tongue may pass through it; and when so turned the lug h will be at right angles to the guardplate, and engage with some fixed portion of the look as its case, so as to act as a stop for holding the guard within the key-hole.

When the nut is screwed up as firmly as may be, the guard is almost immovably fixed in the key-hole, so that it is impossible to dislodge it from without, and the bit and hub being of such size as to nearly or quite fill ordinary key-holes,'it will be impossible also to insert false keys or picking instruments in the lock, the guard-plate at the same time serving to protect the key-hole, so as to prevent seeing through it.

By making the bit-tongue project through the slot m in the guard-plate, the stem f is prevented from turning.

The ends accomplished by securing the hub a, and stem f together by a screw, or other swiveling, turning, sliding, or adjustable joint, are that the parts may be readily separated for packing, the guard-plate and nut being also detached; also, that the guard may be lengthened to fit key-holes of various depths through, and also primarily to permit the turning of the stem in applying the guard to a key-hole.

The hub is of the guard-plate is made tapering toward the bit, so as to enter and be jammed in large or other key-holes, and there by aid in holding the device tightly in place.

By securing the bit-hub and stem f together with a socket-joint, there is nothing of the joint exposed to drilling or filing, and a solid hub is presented on the outside of the lock or door. I g

Having thus described our invention, what we claim is- 1. The slotted guard-plate i, having a feather, n, the grooved stem f, and tongue 0, comable slotted guard-plate, a uard-plate carrybined substantially as and for the purpose ing-stem havingaretainingug, and a bit and specified. hub, substantially as specified.

2. The guard-plate 2', having a tapering M. SOHOU. hub, substantially as and for the purpose set v THOMAS WEST. forth. 7 a I Witnesses:

3. A key-hole guard, consisting of the com- B. A. NAYLOR, bination of a sliding, removable, and adjust- J OHN H. LAIRD. 

